ELECTRON-AFFINITIES OF SI, GE, SN AND PT BY TUNABLE LASER PHOTODETACHMENT STUDIES

The electron affinities of silicon, germanium, tin and platinum are me asured by tunable laser photodetachment spectroscopy via detection of the neutral atomic species. The binding energy values obtained for Si- , Ge- and Sn- (electron configuration np(3) with n = 3 to 5) are 11207 .0(5) cm(-1), 9942.6(4) cm(-1) and 8969.6(5) cm(-1), respectively. The improvements in accuracy over the existing values in the literature f or these three species lie between one and two orders of magnitude. Th e binding energy of the 5d(9)6s(2) D-2(5/2) ground level of Pt- is fou nd to be 17141(6) cm(-1). This result is in relatively good agreement with the two existing results in the literature. Finally, the prospect s for further studies of atomic negative ions are briefly discussed.